It depends on the enabling legislation within your state. Some states allow for the county to be under one "zone", with all uses listed as conditional uses, and any changes are handled by the planning commission as if it were a conditional use hearing.
This is much less breaucratic process, and can be a good foot-in-the-door kind of plan for getting some growth management implemented in rural areas. It is also a real big job to document all the uses and maintain a database of the permitted uses, and actions of the Commission.
What state are you going to try this in?